1. Field of the Invention
The present invention relates to lighting systems, such as architectural and environmental lighting systems. The invention especially relates to cove lighting systems for residential, as well as commercial, applications.
2. Description of the Related Art
In a typical cove lighting system, lighting elements are located in an architectural recess and gently illuminate the wall and/or ceiling space adjacent the recess. Light coves are most frequently located near junctions between walls and ceilings. However, light coves may be placed in other locations, and may be provided in many orientations, including horizontal and vertical.
Cove lighting systems have many applications. For example, cove lighting systems may be used to illuminate book cases, wine and glass racks, furniture, and display-cases. Cove lighting systems may be employed anywhere that the introduction of a soft halo of light is desired.
Examples of lighting elements that have been used for cove lighting systems include incandescent bulbs, PL lamps, and standard fluorescent hot cathode lamps. As explained below, all such lighting elements have significant drawbacks for certain uses.
Incandescent bulbs are energy inefficient. Incandescent bulbs also have a short lifetime. The lifetime of a standard incandescent bulb may be only two thousand hours. Therefore, incandescent bulbs must be replaced frequently. Moreover, incandescent bulbs do not produce uniform illumination. A row of incandescent bulbs produces uneven bright and dark areas of illumination.
A PL lamp is a small diameter U-shaped gas discharge fluorescent lamp. PL lamps, like incandescent bulbs, produce uneven bright and dark areas of illumination. Moreover, PL lamps cannot be dimmed without specialized auxiliary power supplies. Another disadvantage associated with PL lamps is that they are not commercially available in colors other than white. The lifetime of a standard PL lamp is approximately ten thousand hours.
Standard fluorescent (hot cathode gas discharge) lamps are not commercially available in curved configurations suitable for cove lighting applications. Moreover, fluorescent lamps are not commercially available in colors other than white, and are not dimmable without special equipment. The rated lives of commercially available fluorescent lamps are from ten thousand to fifteen thousand hours.
Low voltage cold cathode lamps, in contrast to the lamps discussed above, are especially well suited for cove lighting applications. Cold cathode lamps are dimmable and can be relatively easily fabricated to follow a curved architectural recess without loss of light. Moreover, cold cathode lamps can be ordered in almost any color imaginable, from whites to hot pinks, vibrant blues, purples, and aquas. However, most cold cathode lamps fabricated for low voltage applications are fabricated exactly like standard hot cathode lamps. That is, the electrodes are at the ends of a straight tubular lamp, meaning that the lamp ends are dark.
The dark regions have been overcome in the past by overlapping the unilluminated end portions of the lamps in the fixture. Unfortunately, that involves longer and more expensive lamps and sometimes resulted in bright spots if the lamps overlapped too far, placing two illuminated portions side by side in the fixture. Moreover, a dark region still existed where two fixtures were placed adjacent to each other.
A cold cathode lamp is a gas discharge lamp whose electrodes are not heated to the point of thermionic emission. A hot cathode lamp is a gas discharge lamp-whose electrodes are heated to the point of thermionic emission. Because of this difference, cold cathode lamps may last much longer than hot cathode lamps. A well manufactured cold cathode lamp may last fifty thousand hours. Unlike regular hot cathode fluorescent lamps, a cold cathode lamp does not lose three hours of-its rated lifetime each time it is turned on.
Examples of cold cathode gas discharge lamps are disclosed in U.S. Pat. Nos. 5,155,668 (Tanner) and 4,004,185 (Edmondson et al.), the entire disclosures of which are incorporated herein by reference.
High voltage cold cathode lamps (including conventional neon lamps) have been used for some cove lighting applications with some success. However, high voltage lamps cannot be used in residences. According to the National Electric Code, NEC 410-75A, voltages over one thousand volts are not suitable for residential applications. Standard high voltage cold cathode lamps are particularly hazardous for residential applications. The high voltage operation of such lamps can also cause humming and buzzing noises which are unacceptable for many applications, particularly residential applications.
Another disadvantage with high voltage lamps is that the ends of such lamps electrostatically attract and incinerate dust. The resulting soot accumulates on the ceiling. The higher the voltage, the worse the problem. Eventually, the ceiling has to be repainted to cover the accumulated soot. It may be necessary to repaint the ceiling every year. To avoid the problem of soot accumulation, coves with high voltage lamps may be spaced farther away from the ceiling. However, for architectural and aesthetic reasons, it is generally advantageous to locate a cove as close to the ceiling as possible.
The present invention overcomes the problems of the prior art by providing a modular system of low voltage, cold cathode lighting fixtures connected together in parallel, with each fixture having a self-contained ballast, and with each fixture operating at a voltage of no more than about one thousand volts. The modular system may advantageously include a plurality of straight lamps and at least one curved lamp. Some of the straight lamps may be longer than the others. The modular system may be easy to install.
In a preferred embodiment of the invention, a modular system for generating light comprises a plurality of fixtures. Each fixture includes a casing, a cold cathode lamp supported by said casing, and a ballast for providing power to said lamp. The lamp includes a first tube, a second tube connected to and in fluid communication with the first tube, and a third tube connected to and in fluid communication with the second tube. Preferred embodiments of the invention include a first tube, a second tube formed at 90xc2x0 from the first tube at each end of the first tube and a third tube attached to each second tube and extending parallel to the first tube. Each third tube includes a lamp electrode and is disposed between the first tube and a bottom wall of the fixture. Preferably, the fixtures are electrically connected together in parallel, with each fixture being arranged to operate at a voltage of no more than about one thousand volts.
A lamp base is provided that includes a first portion configured to surround an end of the third tube and a pair of orifices for receiving electrical leads from the electrode. The lamp base includes a second portion configured to receive and to be adhered to a portion of the first tube and protect the third tube from any torque stress or breakage when the electric-lamp is snapped into the lampholder.
In a preferred embodiment, the fixtures operate at voltages of no more than about one thousand volts. Advantageous results are achieved when the fixtures are operated at about six hundred volts. Low voltage operation may be achieved by connecting the fixtures together in parallel and by making the diameters of the cold cathode lamps about three-quarters of an inch or greater. These larger diameters are desired so that the ballast voltage will be significant enough to strike an arc within the lamp. Smaller diameter lamps (sometimes referred to as xe2x80x9cneon lamps,xe2x80x9d with diameters of about five-eighths of an inch and smaller) are far higher in impedance and require voltages far in excess of one thousand volts to strike the arc in a lamp of the same length.
In a preferred embodiment of the invention, the modular system is available as a kit. Modularized, standard lengths of straight fixtures with integral ballasts are provided, along with similarly configured curved, angled or hinged fixtures. Each fixture is wired for easy interconnection, one to another. To install the system, the end user simply places the fixtures along the cove or other recess, connects the fixtures to each other and then connects the system to a suitable line voltage power supply.
The present invention also relates to a cold cathode cove lighting system for residential use. The system includes a cove connected to a wall. In this aspect of the invention, the lighting system is made up of a plurality of differently configured low voltage lamps supported within the cove. The lamps preferably include a first tube that is illuminated completely from end to end, including end surfaces. Thus, the lamps can be disposed adjacent each other in an end to end configuration without dark regions.
In one embodiment of the invention, the ballasts for the lamps are, located within the fixtures, such that the modular system is very easy to install.
In an alternate embodiment of the invention, the ballasts are located outside the cove to make ballast replacement or service convenient when fixtures are installed in difficult to access areas, or to produce a cove lighting system with a very narrow profile.
The casings for the fixtures may be light weight, easy to handle extruded elements. The ends of the casings may be enclosed by vertical plates. In one aspect of the invention, the casings are provided with side openings for aligning the lamps in the desired staggered relationship.
The present invention also relates to a cover for protecting the fixture from the environment. The cover is secured to the casing and sealed against high wind and water entry. The cover can be secured to the casing by mechanical fasteners, such as screws, bolts, rivets or the like, adhesives or any other suitable method. As described in more detail below, the cover may be removably connectable to a casing with a snap fit.
The present invention also relates to a multi-color gas discharge lamp having a plurality of pre-colored tubular sections spliced together to simultaneously produce different colors.
The present invention also relates to a system having a plurality of different color lamps that can be selectively dimmed to provide different resultant colors.
An object of the invention is to provide a safe, attractive, long lasting, and efficient linear continuous line-of-light lighting system.
Another object of the invention is to provide a supply of differently configured light fixtures from which fixtures of different lengths, shapes and configurations can be selected and used to create a uniform illumination cove lighting system regardless of the linear dimensions of a straight cove, and regardless of the locations of the cove""s corners. Hinged and straight fixtures can be combined to illuminate circular or free form radii cove designs.
Another object of the invention is to provide a modular package of linear and non-linear light fixtures, including low voltage cold cathode light fixtures, that can be easily connected together in parallel.
Another object of the invention is to provide a dimmable lighting system with an infinitely variable light output capability.
Another object of the invention is to provide a light fixture system that dims uniformly from fixture to fixture, regardless of the lengths and shapes of the lamps.
Another object of the invention is to provide a lighting system with lamps that have long lives. The system is ideal for use in hard-to-service locations, and will reduce or even eliminate lamp replacement and associated labor costs.
Another object of the invention is to provide a lighting system that easily transitions around angles, corners and radius curves and the like, as found in residential and commercial applications. An object of the invention is to provide a lighting system that avoids the formation of dark spaces between fixtures and in the corners and curves of coves and that can be easily assembled with other lighting fixtures.
Other objects and advantages of the invention will become apparent from the following detailed description and drawings which illustrate preferred embodiments of the invention.